Remove Search Enhanced Results Completely - Get Rid of Search Enhanced Results

Recently I began to notice that when using google search, on Chrome ONLY but not on Firefox, I always got a list of ad on the very top of my search list, with a sign next to those ad's "Search Enhanced Results by not set". I uninstalled Chrome and re-installed a new version but now Chrome runs super slow and the "Search Enhanced Results" thing still shows up at the top of my google search. Need some help.

What is Search Enhanced Results?

What is Search Enhanced Results? How can this infection get into the computer? How to blocking the ads and remove Search Enhanced Results related contents from the computer completely？